Bean Problems and Troubleshooting Tips
Answers To Common Bean Growing Problems
Like any type of plant, you need to understand a bit about what they need in order to both germinate, as well as to thrive, grow, and produce. Beans require sowing at the right time of year so that they begin to produce flowers and pods before temperatures become too hot. (Click here for an informational resource, organized by location, that may be of help.) The right location and conditions are necessary for them to produce good quantities of flavorful, high quality pods. Choose a sunny location that receives 8 to 10 hours of direct sunlight; 5 to 7 hours is a minimum, but can expect much lower yields.
Sometimes, no matter how careful we are as gardeners, Mother Nature is unpredictable and the beans will suffer. Here are some answers to common questions that we receive regarding bean problems.
Q. I planted my beans and a few came up but many did not. Digging them up, they look rotted. What happened?
A. The first, obvious consideration is the quality of the seed. Victory Seeds® are germination tested to meet, and generally exceed, state and federal germination standards when they leave the farm and are ready for planting. If done properly, beans can be stored for several years but germination rates will decline with time. (Click here for more information - /pages/storing#Storage)
Assuming that you are planting quality seed, the most common problem is that people get too excited about planting their spring garden and simply plant them too early. Beans will not "wake up" and start growing into plants if the soil is cold and damp. Green beans and Lima beans, for example, really need sustained soil temperatures above 75ºF to quickly germinate. Refer to /pages/germination-temps for more information.
Q. I planted my beans and a few came up but many did not. Digging them up, they look fine. What happened?
A. Again, assuming that you are planting quality seed after the soil temperatures are warm enough to stimulate germination, the most common problem is that people don't keep their seeds constantly moist. Once a seed is sown, watered, and is re-hydrated, the germination process initiates. If the seeds are then allowed to dry out, it is very likely that they will be killed. Keep your seeds moist until germination occurs and then you can begin backing off and watering your plants as necessary.
Q. A couple of my green beans germinated and started to grow, but they never grew any true leaves. What happened?
A. Commonly referred to as "bald head" or "snake head," there are a couple of things that can cause this to occur. The most common cause is planting seriously damaged seeds. Another is planting in soil that is heavy or that has crusted over. When the seedlings are forced to germinate through this type of soil condition, the seedlings can literally pull their growing heads off in the process. Beans are best sown in loose soil and/or by maintaining adequate soil moisture.
Blooming / Fruiting / Growth Habit Issues:
Q. My beans are growing green, big and healthy but are not flowering. Why?
A. There are several things or combination of conditions, that promotes vegetative growth but not stimulate the reproductive cycle in the plants. Some of these conditions include:
- The soil has excess nitrogen. Since beans are legumes, they do not require super fertile soil and you should limit your fertilizing. If things are going well and pods are developing, once you begin harvesting, a light application of fertilizer can help to increase and improve later harvests.
- If the evening temperatures are too warm, the beans typically won't flower. Raising beans is all about timing your planting at the correct time of the year. Early spring, as soon as the soil warms in your area, is ideal. If you are raising pole beans and your climate gets hot (above about 85ºF), you may experience periods of time when flowering ceases, or does not occur until the days get shorter and cooler.
- Too much water will also promote green growth and inhibit flowering.
- Too little sunlight can be an issue. Beans need a minimum of five to seven hours of full sunlight to produce pods; eight to ten is ideal. Planting at the wrong time of year, growing them indoors without adequate light, choosing the wrong location in your yard, and even planting them too close together can all be considerations.
If you notice, there is a pattern to the above issues. Stress! If a plant "thinks" that everything is great, they just happily chug along, growing and living, but don't start thinking about the future. If you back off the feeding and let them get a little stressed before you water them the next time, they start realizing that they need to begin reproducing in order to preserve their genetics. Of course, their reproductive cycle produces the fruits (beans) that we are after.
Q. My bean plants / vines are flowering but they are dropping off and not developing beans? Or a few beans start developing but drop off when they are small? What is wrong?
A. There are many things that can cause this to occur. In general terms, too much stress is typically the underlying reason. Specific conditions include:
- If it is early in the season, some amount of blossom drop is common but as the season progresses, productivity should improve.
- The temperature is too high and the humidity is low.
- Plants are not receiving enough water or they are receiving too much water.
- Excess nitrogen can cause blossom drop.
Pollination can also sometimes be a factor. Biologically, bean flowers are referred to as "perfect." That is, the flowers contain both male and female parts and typically are typically pollinated even before the flowers open. This means that they technically do not require pollinating insects for reproduction to occur, but insects can help to increase yields.
Q. Help, my bush beans are starting to vine! A. Although bush-type beans tend to be compact and determinate in growth habit, buried within their genetics are vining ancestors. Even though they have been stabilized for generations so as to grow true-to-type, under certain conditions, they can produce short, non-vining runners that can reach up to four feet, or they can even produce full vines. Reportedly, certain fertility, light, and/or temperature conditions in both field and greenhouse plantings, have induced the development of runners on the plants. This rarely occurs, but when it does, it can affect a high proportion of the plants within the population.
Q. Why are my beans getting tough and stringy? What can I do?
A. There is not one specific answer to this question. If you are raising a snap or "green" bean for fresh eating, the pods are best harvest when they are young and tender and before the seeds have begun to develop. Additionally, some bean varieties are better than others in regards to strings. For example, modern bush-type beans developed for mechanical harvesting generally are described as being stringless. On the other extreme, older pole-type beans develop strings and require "snapping" prior to meal preparation or processing.
Many of us older, country folk have memories of our mothers and grandmothers sitting on the porch with a big bowl of beans snapping and de-stringing. (Click here for more information. - www.vintageveggies.com/catalog/vegetable/beans/bean_cooking.html) You might ask, "Why would you want to grow those varieties and do that extra bit of work?" Well, a lot of things in life, some things are worth working for. Older varieties of beans tend to have more complex, pronounced flavors that people describe as possessing an "old-timey bean flavor."
However, even modern green beans can, and will, become fibrous. As most bean pods mature, they naturally become fibrous. Hot weather as the pods are forming and developing can be a cause. Poor soil and inadequate moisture can also contribute to this condition. Plants in stress can be an issue.
Q. Although my bean seeds came up well, they began to die and bend over at the soil level. What happened?
A. This condition, commonly referred to as "damping off," is another fungal problem. It is generally most severe during early spring when the soil is cool and wet. This is why we recommend waiting until your soil warms before sowing your beans. Soil with good drainage, or using raised beds, can help. Refer to /pages/what-is-damping-off for more information about damping off. If you are not an organic gardener, there are fungicides available to treat the seeds prior to sowing that can help you get an earlier start.
Q. My plants are really stunted and when I pulled one up, there were large "tumors" growing on the roots. What is going on?
A. In healthy plants, you will see small nodules attached to the roots which are formed by beneficial, nitrification bacteria. This is a symbiotic process that all legumes have giving then the ability to "breath in" atmospheric nitrogen and fix it into their root system. This is also why legumes do better in poorer soils than leafy green plants.
Back to the question, if the plants are unhealthy and have swellings, referred to as galls, and your plants are being attached by root knot nematodes that are literally sapping the life from your beans. These bad nematodes live in your soil and can survive on many types of plants. One control method is to plant rye as an over winter cover crop and then mow it and till it into the soil at least 30 days prior to planting your garden in the spring.
Q. My bean leaves are turning yellow on top and has a dusty, brown material on the bottom.
A. This condition, generally associated with cool weather, is caused by a fungus called Bean Rust. If this disease is a common problem in your area, try growing rust resistant bean varieties. If it seems to be limited to on plant, immediately remove the affected plant and discard in your trash (not your compost pile), or immediately begin treating with an appropriate fungicide such as sulfur. Repeated applications will be necessary to control.
Q. My bean leaves look crumpled or distorted and have a mottled pattern developing.
A. Your plants have probably contracted a bean mosaic virus. This is transmitted from plant to plant by aphids so the best control methods are to quickly remove and discard diseased plants and focus on controlling the aphids.
Q. My bean leaves have large brown spots on them and seem to be more affected near the soil?
A. There are a lot of things that can cause leaf spots on beans; too many for a simple Q&A. In general, be very careful when watering so that you don't splash soil, and the diseases it contains, onto your plants. Drip irrigation is preferred. Secondly, try removing the affected leaves as they present and see if the issue resolves. For more accurate identification and troubleshooting, contact your local Agricultural Extension Agent or Master Gardeners.